Nebraska’s Loess Canyons are a Case Study in Halting Woody Encroachment

Story by Casey Sill, QF Public Relations Specialist
Photos by Eric Fowler of Nebraskaland Magazine

Dirac Twidwell doesn’t hate cedar trees, but that doesn’t stop him from telling people to light them on fire.

The University of Nebraska-Lincoln rangeland professor respects their tenacity in a certain way. Eastern red cedars have the uncanny ability to thrive if given even the slightest window of opportunity, and Twidwell appreciates that kind of ecological stubbornness.

Eastern red cedars are a primary driver of woody encroachment across the country. Cedar and other species are taking over areas where they were previously absent, creating major issues for ecosystems, particularly on the Great Plains. Encroachment is most common on grasslands, and the Great Plains of the American Midwest are a hotbed for the advancement of this “green glacier.”

“When people think of a species coming in and taking over, they typically think of non-native, invasive species,” Twidwell says. “But it can be done by native species as well. They’re spreading into nearby ecosystems where they were previously either incredibly rare or completely absent.”

The problem seems daunting when you look at it statistically. Millions upon millions of acres have been lost to woody encroachment in recent decades — Nebraska alone has lost over 3 million acres to cedars since the 1990s. The concept of stopping the spread can sometimes feel like trying to bail out the Titanic with a 5-gallon bucket and a sponge. But for the last 20 years, landowners in Nebraska’s Loess Canyons have proven you can not only stop, but reverse the advance.

While woody encroachment has been occurring for decades in the southern Great Plains, cedar invasion only recently started to increase in Nebraska and other northern states. The culprit of their spread is fire – or rather the lack of it. For centuries, both native cultural burning and regular wildfires kept woody encroachment at bay. Historically, one-third of tall grass prairie in the Great Plains burned every year, according to Twidwell. All the way from Minnesota to Texas.

Native tribes used fire to kickstart new growth and attract buffalo with fresh, green grass. Lightning strikes added to the use of prescribed fire, and together they kept the grasslands in check. All this changed as European settlers moved west.

“We removed the cedar’s natural enemy (fire) from the landscape,” Twidwell says. “And we also planted it into very intact grasslands like the Nebraska Sandhills. Every ranch has a cedar-based windbreak. All of them. And it’s not just in Nebraska, we did that across the Great Plains. Those two things created a perfect storm for cedar.”

Eastern red cedars can eat up large swaths of prairie and ranch land in a short period of time, leading to all kinds of problems for both landowners and the grassland species that call these areas home. Heavy canopy cover deteriorates the health of grassland ecosystems and dramatically raises the threat of catastrophic wildfires by increasing the fuel load on the landscape.

The reduced quality of grasses also greatly impacts the grazing productivity for cattle ranchers. Woody encroachment can reduce rangeland production by as much as 75%, according to multiple scientific studies.

For countless ranchers, farmers, and landowners in middle America, this combination of factors makes cedar encroachment seriously detrimental to both their livelihood and their communities.

Stretching across southwestern Nebraska for nearly 350,000 acres, the Loess Canyons are appropriately named. In a state known for being mind-numbingly flat, here the landscape is filled with rolling pastures, steep hillsides, and rugged canyons. The area is not terribly useful for farming, but is ideal for grazing cattle, which has been the dominant use of the Loess Canyons for generations.

The steep terrain is also a perfect breeding ground for cedar trees, which began to spring up in greater numbers across the canyons in the latter half of the 20th century. At the time, no one had a reason to be alarmed at their expansion. Until that point, tree growth had almost always been seen as positive.

“Back in the day folks used those woody species to stay warm, to build houses, and so on. A lot of growth got used up,” says Scott Stout, whose family runs a fourth-generation ranch in the Loess Canyons. “By the time we got to the 1950s and 60s, if a tree was growing, they thought that was the greatest thing in the world.”

No one saw cedar encroachment as a threat to grazing lands well into the 1990s, according to Stout. Right around the time of Y2K, attitudes started to change.

“In the late 1990s, we really started to see the issue,” Stout says. “That’s when cedars started to impact our grazing and a lot of the other things we were doing to sustain a living.”

Here is where the Loess Canyons story departs from many other locations across the Great Plains. Not long after recognizing cedars as a major issue, local communities in the area decided to do something about it.

In 2002 residents founded the Loess Canyons Rangeland Alliance (LCRA) to try and combat woody encroachment. The early years of the LCRA were mostly experimental and yielded mixed results. They knew fire was the best tool they had at their disposal, but hadn’t yet mastered its use.

“At first it was just a few landowners doing small burns of a couple hundred acres,” Stout says. “A lot of landowners in the area still had a fear of fire, and it wasn’t necessarily looked at as beneficial.”

Stout got involved with the LCRA around 2005 and conducted the first burn on his property in 2008. As more and more landowners started to see the value of prescribed burns, the alliance grew, and their output skyrocketed.

“From about 2008 on, it seemed like the roller coaster was downhill all the way. Everybody was jumping on board and things were moving fast,” Stout says. “We went from having 8 to 10 members to 60 or 70.”

This buy-in from the community is precisely what has allowed the LCRA to be so successful in the years since.

Cedar expansion is initially invisible. If you look at a stand or windbreak of cedars surrounded by intact grasslands, the reach of those trees extends far beyond the space they’re currently occupying. One of the only ways to truly stop encroachment is to kill not just existing woody cover but burn surrounding grasslands that have been contaminated by seed.

“Encroachment is not when you’ve lost your grassland,” says the University of Nebraska’s Twidwell. “Encroachment happens when seed is being dispersed, leading to new seedlings hidden in your prairie. You can’t see it yet, but it’s there.”

Meaning, landowners can burn all they want on their property, but it won’t do any good if they’re not working alongside their neighbors to fight encroachment on the larger landscape. You have to get out in front of the issue, according to Twidwell.

“Everything used to be structured to wait until we had enough cedar cover on the landscape, then you would ‘restore’ it back to the way it was,” he says. “But that puts you in a perpetual mode of restoration.”

Collaboration is key, and this is where the LCRA struck gold. Today, members of the LCRA and it’s partner burn association, the Central Platte Rangeland Alliance, collectively own the majority of the 350,000-acre eco-region.

“The Loess Canyons is one of the few examples where a culture of prescribed fire has been restored at that kind of scale after having been lost in the Great Plains,” Twidwell says. “More of it is happening now, but they’re one of the few.”

Through trial and error, the LCRA has also refined their process, allowing for hotter fires and better results at each burn. Much of this has been accomplished by what’s known as cutting and stuffing, according to Stout.

“We take the trees we’ve sheered or cut in areas we can get to and shove that into live trees in areas we can’t get equipment into, which creates a continuous pile along the base and topsides of those areas where you cannot sheer the trees,” he says. “By doing that, you have a dried fuel source at the top and bottom of each hill, and that accelerates the amount of heat under those trees and carries up through the live tree source.”

The combination of community partnership and experience has led to incredible results for the LCRA and their local ecosystem. To date the alliance has impacted nearly 100,000 acres in the Loess Canyons. But more importantly to Stout, they often achieve a 90% morality rate during those burns.

“It’s not just the amount of acres you’re burning, it’s the amount of good you’re doing when you burn them,” he says. “What I like to lay my hat on is that consistent 80 to 90% mortality. When you’re getting back 80% of your grazing acres, that makes a big difference.”

Twidwell holds the Loess Canyons and the LCRA up as a shining example of what can be done to fight against the seemingly unstoppable encroachment of the eastern red cedar. With community partnership, the cedar’s advance can be stopped.

“This is the first place we have ever documented where people have successfully halted the regional expansion of eastern red cedar,” he says. “That success is because the Loess Canyons is one of the only examples in the world where a community of private landowners resurrected a culture of fire. The science shows it’s not only possible to restore fire at large scales, but it’s also one of the best ways to save the grasslands that support our way of life and well-being in the Great Plains.”

Stout is proud of what the LCRA has accomplished and is optimistic about the future of cedar encroachment in the Loess Canyons. That optimism does not apply to everywhere in the Great Plains, but he said the collaboration that’s made them so successful is possible anywhere.

“Landowners have been getting together to help each other for centuries, whether it be branding time or helping your neighbors harvest,” he says. “It’s how rural communities operate. We’re just adding fire to the mix.”

This story originally appeared in the Spring 2025 issue of Quail Forever Journal